A PC built into the car is great for all kinds of reasons:
  • More flexible GPS software than dedicated units
  • Wireless Web Access that's bigger than a deck of cards
  • Support for 7.1 surround sound processing
  • Multiple music formats better than MP3 like Ogg, FLAC, etc
  • Connect to your OBDII port and get all kinds of life and logged status info from your car and potentially tweak engine and other car parameters on the fly
  • Games
  • Video recording from multiple cameras simulatenously
The list goes on and on, only limited by your imagination unlike a dedicate system that only does one thing and often can't be upgraded.